Within 2 hours of cooking food or after it is removed from an appliance keeping it warm, leftovers must be refrigerated. Throw away all perishable foods that have been left in room temperature for more than 2 hours (1 hour if the temperature is over 90° F, such as at an outdoor picnic during summer).

How long can leftovers be left unrefrigerated?

The "2-hour rule" states that perishables left at room temperature for more than two hours should be discarded. If the food is being kept in an area that is 90 degrees Fahrenheit (32.2 degrees Celsius) or above, leftovers should be refrigerated to 40 degrees Fahrenheit (4.4 degrees Celsius) or below within one hour.

Do leftovers go bad if not refrigerated?

The USDA says food that has been left out of the fridge for more than two hours should be thrown away. At room temperature, bacteria grows incredibly fast and can make you sick. Reheating something that has been sitting at room temperature for longer than two hours won't be safe from bacteria.